The present invention relates to an IC socket adapted to electrically connect an IC package to a printed board and also relates to a method of assembling the IC socket.
Such IC package is so called, in the known art, a ball grid array (BGA), which has a structure in which a number of spherical terminals are arranged in a grid (lattice) form to a lower surface of a rectangular package body so as to project outward therefrom.
An IC socket generally has a socket body, a mount portion formed to the socket body, on which the IC package is mounted, and a number of contact pins disposed to be elastically deformable so as to contact or separate from the terminals of the IC package.
The contact pins are press-fitted into insertion holes formed to the socket body and fixed thereto, these portion being called fixed portions, and on the upper side of the fixed portions, contact portions as elastically deformable xe2x80x9cone end portionsxe2x80x9d are formed so as to contact or separate from the terminals of the IC package. Lower end portions as xe2x80x9cother end portionsxe2x80x9d projecting downward from the fixed portions are inserted into through holes of the printed board and then soldered and fixed to the printed board.
An upper operation member is provided to the socket body to be vertically movable, and when the upper operation member is moved downward, a movable plate, which is provided to the socket body to be slidable in a horizontal direction, is slid. When the movable plate is slid, the contact pins are pressed by the movable plate and the contact portions thereof are elastically deformed, and at this time, the contact pins are retracted from a terminal insertion range. On the other hand, when the upper operation member is moved upward, the movable plate returns and the contact pins come back their positions due to their elastically deformable property so as to contact the terminals of the IC package.
In the conventional IC socket of the structure mentioned above, however, recently, it is required to reduce a distance between the respective terminals of the IC package, and hence, it becomes difficult to manufacture a printed board so as to accord with such reduced distance of the terminals. That is, because it is necessary for the printed board to form wirings between the respective though holes, in the arrangement in which the distances between the respective through holes in the lattice arrangement are made small, it is difficult to arrange the wirings of the number corresponding to the number of the terminals between the respective terminals.
An object of the present invention is to substantially eliminate defects or drawbacks encountered in the prior art and to provide an IC socket capable of electrically connecting an IC package and a printed board even if terminals of the IC package are arranged with reduced distances from each other and also provide a method of manufacturing such IC socket.
This and other objects can be achieved according to the present invention by providing, in one aspect, an IC socket adapted to establish an electrical connection between an IC package and a printed board, comprising:
a socket body having a mount portion on which the IC package is mounted;
a number of contact pins disposed on the socket body in substantially equally adjacent arrangement, each of the contact pins having one end to be connected to a terminal of the IC package and another end to be connected to the printed board; and
means provided for the socket body for widening an interval between the another ends of adjacent contact pins so as to provide a predetermined distance therebetween.
In preferred embodiments, the interval widening means comprises a converter unit arranged with a predetermined interval from the socket body and the converter unit is formed with through holes which are arranged at a predetermined intervals therebetween and into which the contact pins are inserted and is provided with guide means for guiding the contact pins projecting from the socket body toward the through holes while widening intervals between the other ends of the contact pins.
The guide means is composed of guide projections integrally formed to the converter unit so as to project toward the socket body. The converter unit is composed of a first converter member and a second converter member opposing to the first converter member, and the guide means is formed to the second converter means, the first converter member being formed with insertion holes through which the contact pins are inserted and extend therefrom toward the through holes formed to the guide means.
The insertion holes formed to the first converter member correspond to the through holes of the second converter member in lattice arrangement and a distance between adjacent through holes of the second converter member is wider than a distance between adjacent insertion holes of the first converter member. Each of the guide projections has a projecting end portion having an inclination so as to make wide the interval between the adjacent contact pins at a time when the contact pins are inserted into the through holes of the second converter member. The guide means comprises a plurality of rod members disposed between the contact pins, respectively, so as to be inserted thereinto and withdrawn therefrom. The converter unit is composed of a first converter member and a second converter member opposing to the first converter member, the first converter member is formed with insertion holes through which the contact pins are inserted, and the second converter member is formed with through holes, the rod members being inserted between the first and second converter members.
The socket body is formed with a plurality of insertion holes through which the contact pins are inserted, each of the insertion holes having an inclination along an inserting direction of the contact pin at the one end of the contact pin so as to make wide an interval between another ends of adjacent contact pins.
The IC package has a plate structure having one surface on which a number of terminals are arranged in substantially lattice shape.
The other ends of the contact pins are elastically deformed so as to make wide an interval between the other ends of adjacent contact pins to a predetermined distance.
In another aspect of the present invention, there is provided a method of assembling an IC socket adapted to establish an electrical connection between an IC package and a printed board and comprising a socket body having a mount portion on which the IC package is mounted, and a number of contact pins disposed on the socket body in an adjacent arrangement, each of the contact pins having one end to be connected to a terminal of the IC package and another and to be connected to the printed board, the method comprising the steps of:
preparing means for widening a pitch interval between the another ends of adjacent contact pins to a predetermined distance therebetween, said widening means being provided with a guide means;
moving the widening means to the socket body so that the contact pins are guided along the guide means while widening an interval between the adjacent contact pins; and
mounting the widening means to the socket body in a state of the interval of the adjacent contact pins being widened.
In a preferred embodiment, the widening means is a converter unit formed with through holes into which the contact pins are inserted and guided so as to widen the interval between the adjacent contact pins to a predetermined distance.
According to the present invention of the structures and characters mentioned above, the interval of the adjacent contact pins to be connected to the printed board is widened to a predetermined distance by the suitable interval widening means, so that even in a case of a small interval between the adjacent terminals formed to the IC package, it is not necessary to prepare the printed board having the small interval corresponding to that of the terminals, thus being advantageous and economical.
Furthermore, since the other ends of the contacts pins are formed to be elastically deformable to widen the interval between the adjacent contact pins, the assembling working can be made easy and simple in comparison with a conventional technology in which contact pins are plastically deformed so as to have different angles respectively of the other ends of the contact pins. Thus, according to the present invention, the end portions of the contact pins can be deformed easily at a desired angle to widen the interval of the adjacent contact pins.
The nature and further characteristic features of the present invention will be made more clear from the following descriptions made with reference to the accompanying drawings.